Mobile social networks have been gaining increasingly popularity in the past couple of years. A recent survey by UK's Office of Communications (Ofcom) shows high penetration ratios of mobile social network in various countries (see Table 1). A report from Morgan Stanley also shows that users have a growing tendency to access their social networks more often by smartphones than desktop computers or laptops (see FIG. 1). Among all mobile social networking services, geo-social networking, which enables mobile users to interact based on their locations at any time and any place, is among the most appealing ones. For example, the Google Latitude service enables you to visualize the locations of nearby friends on a map and launch social activities such as chatting or collaborative filtering. As a typical example, you may ask your nearby friends “Where can I find good pizza around here?”. A variety of similar services have been populated in the market, by either social network giants like Facebook, or specialized vendors like Foursquare, Gowalla, or Loopt.
TABLE 1Mobile Social Network User Penetration (Source:Ofcom Consumer Research, October, 2010)CountryUKFRAGERITAUSAJPNPenetration rate %242313182222